Fibroblast growth factors are large polypeptides widely expressed in developing and adult tissues (Baird et al., Cancer Cells, 3:239-243, 1991) and play crucial roles in multiple physiological functions including angiogenesis, mitogenesis, pattern formation, cellular differentiation, metabolic regulation and repair of tissue injury (McKeehan et al., Prog. Nucleic Acid Res. Mol. Biol. 59:135-176, 1998). According to the published literature, the FGF family now consists of twenty-two members (Reuss et al., Cell Tissue Res. 313:139-157 (2003)).
Fibroblast growth factor 21 (FGF-21) has been reported to be preferentially expressed in the liver and described as a treatment for ischemic vascular disease, wound healing, and diseases associated with loss of pulmonary, bronchia or alveolar cell function and numerous other disorders (Nishimura et al., Biochimica et Biophysica Acta, 1492:203-206, (2000); U.S. Pat. No. 6,716,626 and WO01/18172). More recently, FGF-21 has been shown to stimulate glucose-uptake in mouse 3T3-L1 adipocytes in the presence or absence of insulin, and to decrease fed and fasting blood glucose levels in ob/ob and db/db mice and 8 week old ZDF rats in a dose-dependant manner, thus, providing the basis for the use of FGF-21 as a therapy for treating type 2 diabetes and obesity (WO03/011213).
The present invention is based on the finding that the fusion of a protein with a long circulating half-life, such as the Fc portion or an immunoglobulin or albumin, to a FGF-21 compound results in a biologically active, FGF-21 fusion protein with an extended elimination half-life and reduced clearance when compared to that of native FGF-21.
The FGF-21 fusion proteins of the present invention have greater usefulness as a therapeutic as well as greater convenience of use than wild-type FGF-21 because they retain all or a portion of the biological activity of wild-type FGF-21 yet have an extended time action when compared to that of the wild-type FGF-21.
Therefore, FGF-21 fusion proteins of the present invention are useful to treat subjects with disorders including, but not limited to, type 2 diabetes, obesity, and metabolic syndrome, with particular advantages being that the FGF-21 fusion proteins of the present invention have improved efficacy due to constant exposure and require fewer doses, increasing both the convenience to a subject in need of such therapy and the likelihood of a subject's compliance with dosing requirements.